Of course, and with a demo account this can be a good option to choose, they will be able to use it but only to play not with some withdrawals like when on a real account. But this looks good enough to choose when we don't want to lose money at all, and by playing on a demo account at least this will slightly treat our curiosity when we may not have capital to bet, the casino has presented it to be used. For the problem of addiction itself, it is clear that most likely they will not experience it if they only play on a demo account, because on average what makes gamblers addicted is some of the big wins they have gotten and they are greedy by wanting more other wins and in such conditions it is certain that they will lose more money than what they imagine. Demo accounts can be utilized and can also be an option, but you must also remember that even though you are only playing on a demo account, it can potentially lead you to a real account with real stakes. Keep your boundaries in place so that you don't get lured into something that you think will be more interesting when it's just a lure.
The casino or the game provider will always have different settings for both modes, demo mode generally comes without much restrictions such as limited wins, lesser RTP percentage, no house-edge at all, and all these settings make a big difference in the amount of wins and loses a person will get.
For this I agree with you, the purpose of the casino creating a demo account is most likely to lure some of those who are interested in gambling but don't want to lose money, and then they will try it on the demo account first, they will enjoy a few spins there even without real withdrawals if they win, believe me after that they will be lured to try to do it on the real account, with the few wins they managed to get on the demo account will indirectly lead them to jump to the real account because they will think that it is this easy to get a win without them knowing that this is the casino's goal to bring them to real gambling and losing will dominate them there. The demo account and the real account are obviously very different, and it is very likely that the winnings on the demo account will lead them to the real account.